1. Field of the Invention
The present invention relates to a radio communication, and more particularly, to method and apparatus of transmitting data based frequency hopping.
2. Related Art
A frequency hopping spread spectrum (FHSS) method is a kind of spread-spectrum technique in which a signal is transmitted while changing a carrier frequency by using a pseudo-random sequence.
The FHSS may transmit and receive data by randomly hopping a frequency channel based on a random hopping sequence throughput a plurality of channels. As one of embodiments of the FHSS, a pre-scanning for a target channel may be performed before randomly channel hopping is performed. When noise or radio interference exists in a target channel to be hopped, hopping to another channel may be automatically performed by a system by avoiding the corresponding channel. The FHSS method has advantages that security is excellent, the FHSS is strong to narrowband interference, and a frequency channel diversity gain is large, as compared with a transmission method using a fixed frequency. Particularly, due to a characteristic that the security is excellent, the FHSS was referred to as a candidate for military communication.
A single-stream cycle period division multiple access (CPDMA) implemented by a block transmission method using a cyclic prefix may transmit data symbols having a correlation by loading into different subcarriers which are separated from a frequency axis at a regular distance. The CPDMA may be strong to narrowband interference and have large frequency channel diversity. Since a structure for implementing the single stream CPDMA includes a carrier weighting filter, a frequency used for transmitting a signal of a predetermined block may be arbitrarily selected.